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Biomedical subjects

A J van Vught

Publications and source records attributed to A J van Vught.

16 recordsLinked to original sources
PubMed1992

Pulmonary hypertension complicating a ventriculo-atrial shunt.

The use of ventriculo-atrial shunts for CSF diversion in developing hydrocephalus has become rare because of the risk of chronic thrombo-embolism and subsequent pulmonary hypertension associated with an unfavourable prognosis. However, there remains a group of patients in whom ventriculo-atrial shunts have been inserted in the past. In this group, complications can occur after many years. We report on a 13-year-old girl with pulmonary hypertension caused by chronic thrombo-embolism from a ventriculo-atrial shunt.

Adolescent↗
PubMed1991

[Magnesium poisoning in an infant].

We present the case of a girl aged 3 weeks with extreme hypermagnesaemia (7.94 mmol/l) due to an overdose of magnesium oxide, prescribed as a laxative. We treated her successfully with a combination of hyperhydration, forced diuresis and natriuresis, and additional intravenous calcium and insulin. We also performed an exchange transfusion which, however, had a questionable effect on the final outcome.

Combined Modality Therapy↗
PubMed1991

[Shock in children; no child's play].

Shock comprises of circulatory insufficiency accompanied by a discrepancy between oxygen demand and supply at tissue level. This results in tissue hypoxia, which when persisting, can lead to (severe) organ failure. In this article we will discuss pathophysiologic backgrounds of shock following the mechanisms that cause hemodynamic deterioration and tissue hypoxia. Subsequently the role of various cytokines in the pathogenesis of septic shock, which occurs relatively frequent in childhood, are discussed. As far as fluid substitution and vasoactive medication is concerned, therapeutic strategies can be chosen more rationally these days. This is mainly due to the availability of smaller i.v. cannula, central venous catheters and advances in (non) invasive hemodynamic measurements in childhood e.g. central venous pressure, cardiac output, peripheral vascular resistance and left ventricular shortening fraction. Despite these developments, shock (in particular septic shock) remains to have a high mortality, also in childhood.

Child↗
PubMed1991

[Artificial ventilation, a special interaction of pulmonary mechanics and gas exchange].

During artificial ventilation the lungs are intermittently insufflated by respiratory gases in a certain pattern (ventilatory conditions). The consequences in terms of stretch of lung tissue, airway pressure, alveolar pressure and gas exchange depend on the mechanical properties of airways, lung tissue and thoracic wall. These properties are age dependent and may be changed considerably by disease. The basic principles of ventilatory support can be explained as an interaction of ventilatory gases passing through the airways in and out of the lungs, the subsequent changes in stretch of lung tissue and thoracic wall and pressure variations in the airways and alveoli. Overstretched lung and airways tissue causes damage (barotrauma, air leakage). During artificial ventilation intrathoracic pressure increases, which diminishes venous return to the heart and decreases cardiac output. In addition, the sometimes inevitably high oxygen concentrations may be toxic. In this article the ventilatory cycle is analysed into its different sequences and the interaction with the respiratory system and its consequences are discussed.

Cardiac Output↗
PubMed1990

Alveolar pressure during high-frequency jet ventilation.

We studied the influence of ventilatory frequency (1-5 Hz), tidal volume, lung volume and body position on the end-expiratory alveolar-to-tracheal pressure difference during high-frequency jet ventilation (HFJV) in Yorkshire piglets. The animals were anesthetized and paralysed. Alveolar pressure was estimated with the clamp off method, which was performed by a computer controlled ventilator and which had been extensively tested on its feasibility. The alveolar-to-tracheal pressure difference increased with increasing frequency and with increasing tidal volume, the common determinant appearing to be the mean expiratory flow. The effects in prone and in supine position were similar. Increasing thoracic volume decreased the alveolar-to-tracheal pressure difference indicating a dependence of this pressure difference on airway resistance. We concluded that the main factors determining the alveolar-to-tracheal pressure difference (delta P) during HFJV are expiratory flow (V'E) and airway resistance (R), delta P congruent to V'E x R.

Airway Resistance↗
PubMed1989

[Acute cyanide poisoning in an infant].

An infant of 9 months was admitted to hospital in comatose condition; cyanide poisoning was suspected. This poisoning was caused by the desorption of hydrocyanic acid from building materials after the house had been fumigated with hydrocyanic acid under strict supervision and observed safety measures. Administration of 4-dimethyl-aminophenol, a methaemoglobin inducer, and sodium thiosulphate together with supportive measures, led to complete recovery of the infant, although the general hypotony persisted for a few weeks.

Aminophenols↗
PubMed1989

[Home monitoring of infants: a literature review (1972-1987)].

In the Netherlands home-monitoring of infants has been used since 1978, although not as widely as in other countries. For years it has been discussed whether a cardio-respiratory monitor can prevent SIDS. Controversies still exist about the criteria for home-monitoring and the reliability of the device. In this article, the history of debates on home-monitoring since 1972 is reviewed as well as current opinions and controversies.

Home Care Services↗
PubMed1987

Suppression of spontaneous breathing during high-frequency jet ventilation. Separate effects of lung volume and jet frequency.

The effect of ventilatory frequency of high-frequency jet ventilation (HFJV) from 1 to 5 Hz, apart from changes in thoracic volume, on spontaneous breathing activity was studied in Yorkshire piglets under pentobarbital anesthesia. The highest PaCO2 at which the animals did not breathe against the ventilator (apnea point) was established either by changing minute volume of ventilation or by adding CO2 to the respiratory gas. The higher the apnea point, the higher the suppression of spontaneous breathing activity was assumed to be. If the apnea point was searched for by changing minute volume a progressive increase of suppression of spontaneous respiratory activity was found at ventilatory rates of 3 Hz or more, concomitantly with a rise in end-expiratory pressure (PEE). In case the tidal volume was kept constant, increase of ventilatory rate resulted in a tremendous increase of lung volume, together with considerably higher levels of PEE. When under these conditions the apnea point was searched for by adding CO2 to the respiratory gas a much higher CO2-drive was needed for spontaneous breathing and therefore a much stronger inhibition of spontaneous breathing was concluded. By placing the animals in a body box in which pressure could be varied, thoracic volume could be kept constant during HFJV. When thoracic volume was kept constant in this way a constant tidal volume at increasing jet frequencies resulted in only a slight increase in suppression of spontaneous breathing. We conclude that the increase in lung volume is a major factor in suppressing central respiratory activity during HFJV. Jet frequency by itself might be an additional suppressive factor.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

[Reye's syndrome].

Reye's syndrome, characterized by acute encephalopathy and fatty degeneration of the viscera with hepatic failure, is a life-threatening illness that affects children of all ages. Although Reye's syndrome has been investigated extensively, its etiology and pathogenesis remain obscure. Metabolic pathophysiology appears to include a process affecting liver mitochondria. Recently disturbances in fatty acid oxidation have been described with a similar clinical picture. The cause of these events is presumably related to triggering viral illnesses, in ways that are unclear. Since prompt treatment might provide a better chance for recovery, early diagnosis is important.

Brain Diseases↗
PubMed1986

Suppression of spontaneous breathing during high-frequency jet ventilation. Influence of dynamic changes and static levels of lung stretch.

Conditions which suppress spontaneous breathing activity during high-frequency jet ventilation (HFJV) were analysed in Yorkshire piglets under pentobarbital anesthesia. The highest PaCO2 at which the animals did not breathe against the ventilator (apnea point) was established during different patterns of ventilation, either by changing the minute volume or by adding CO2 to the inspiratory gas. Arterial oxygen tension was maintained throughout the study above 80 mm Hg. An elevation of ventilatory rate increased the apnea point, suggesting a progressive suppression of spontaneous breathing. This suppression did not depend on the amount of lung stretch during insufflation, because at higher rates lower tidal volumes were used. Suppression also appeared to be independent of insufflatory flow, i.e. the velocity of lung stretch. At higher frequencies end-expiratory airway pressure (PEE) increased and there appeared to be a positive relationship between the apnea point and PEE. In a separate series this positive relationship between the apnea point and PEE was confirmed. A hysteresis effect in this relationship, however, suggests that other than jet frequency, lung volume rather than positive end-expiratory pressure (PEEP) is a major determinant of suppression of spontaneous breathing activity during HFJV.

Animals↗
PubMed1985

The hemolytic-uremic syndrome: prognostic significance of neurological abnormalities.

To define the prognostic significance of neurological symptoms in the hemolytic-uremic syndrome (HUS), the records of 68 patients with this syndrome were reviewed. Major neurological symptoms (convulsions and/or coma) occurred in 22 patients. Nine of them had dysregulation of breathing as well. An analysis of other symptoms and characteristics of the disease in these 9 patients revealed a rapid progression of the disease, a high incidence of colitis, and a high mortality rate (8 of the 9 patients) despite adequate seizures control, replacement of renal function and assisted ventilation. We conclude that the prognosis of HUS patients with severe neurological symptoms including dysregulation of breathing is poor.

Brain↗
PubMed1976

Hypertensive encephalopathy in childhood. Diagnostic problems.

Oppenheimer and Fischberg's vasoconstriction-hypothesis on the pathogenesis of hypertensive encephalopathy was subsequently supported by animal experiments. Later on the role of decompensation of the autoregulatory mechanism of the cerebral blood flow was revealed. The transient symptomatology comprises headache, seizures, focal cerebral symptoms (hemiplegia etc.), visual disturbances, mental disorders, papiledema etc. The age-dependency of the influence of edema is probably expressed by the predominance of seizures in childhood and the long duration of the symptoms in our third and fourth patient. The differentiation between hypertensive encephalopathy and a local complication of hypertension (hemorrhage) can be difficult, not at least because the first disturbance may be followed by the second (patient 3). Hypertension is not always present as initial symptom (patient 1 and 2). Hence a series of blood pressure readings is required in acute cerebral incidents in childhood. Steroid-treatment may lead, especially in patients suffering from a hypocomplementemic form of membranoproliferative glomerulonephritis, to a sudden rise of the blood pressure and subsequently to hypertensive encephalopathy (patients 2 and 3). Hypertensive encephalopathy is a neuropediatric emergency. The urgent treatment with dioxaside, fursemide and sodium nitroprusside is shortly reviewed.

Adolescent↗